The 16-pin accessory connector on the rear panel provides comprehensive access to audio, data, and control lines. Pin Number Description Signal Characteristics Negative audio output to external speaker Bridged audio output; do not ground 2 Microphone Audio External microphone input 80mV RMS for 60% deviation 3 Digital In 1 Programmable input (e.g., External PTT) Active low, standard TTL logic 4 Digital Out 1 Programmable output (e.g., External Alarm) Open collector; max 250mA 5 Flat TX Audio Direct modulator input Bypasses pre-emphasis and filtering 6 Digital In 2 Programmable input Active low 7 Chassis and signal ground 0V reference 8 Digital Out 2 Programmable output Open collector 9 Digital In 3 Programmable input Active low 10 Ignition Sense Vehicle ignition switch input Positive voltage turns radio on 11 Flat RX Audio Unfiltered receiver discriminator audio Constant level, independent of volume 12 Digital In/Out 7 Bidirectional programmable line TTL levels 13 Switched B+ Regulated power supply output Matches supply voltage; max 1A 14 Digital In 4 Programmable input Active low 15 Received Signal Strength Indicator DC voltage proportional to RF signal 16 Positive audio output to external speaker Bridged audio output; do not ground Front Microphone Connector (RJ45)
Ensure you are running the latest firmware version to fix known bugs in the MDC1200 signalling logic. Conclusion motorola gm3688 service manual exclusive
Enables hands-free operation when connected to compatible accessories like visor microphones, helping drivers maintain focus on the road. The 16-pin accessory connector on the rear panel
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Use a T15 Torx driver to access the main board and PA board. Do you have access to a